1. Field of the Invention
This application relates generally to means for evaluating the contact between occluding teeth and more particularly concerns a composition for marking the contact points on the occlusal surface of a dental restorative or of one natural tooth of a pair of occluding teeth.
2. Description of the Prior Art
In preparing various types of dental restoratives from mouth impressions and in improving occlusion of certain or all of the natural teeth, difficulty has oftentimes been experienced in accurately contouring the occlusal surface of the dental restorative or of the natural tooth. Improper contouring of such occlusal surfaces can cause paradental diseases, such as phyorrhea alveolaris.
Prior art methods to facilitate such contouring have generally employed bite paper, typewriter ribbon, wax or other similar material which was inserted between the occlusal surfaces in order to determine the contact points or the mode of contact between the upper and lower occlusal surfaces of a pair of occluding teeth. Use of such devices does not permit accurate evaluation of the three-dimensional contact between the occlusal surfaces of such teeth. The relatively large thickness of each of such devices prevents the occlusal surfaces from attaining their natural and properly occluding relationship and results in erroneous marking of points which are not truly the contact points between the occlusal surfaces. Further, such devices prevent visual observance of the biting contact between the occlusal surfaces and thereby hinder evaluation of such contact.
In addition, when used, such devices quickly become dry and brittle and, in such a state, make it extremely difficult to accurately mark the contact points between the occlusal surfaces. Such devices also cause an inordinate amount of strain in certain areas of a restorative occlusal surface whereby subsequent removal of the strain therefrom requires a difficult and awkward manipulation. Moreover, use of such devices is often difficult and time consuming. For example, it is impossible to insert more than one of such devices, such as two different kinds of bite papers, between the occlusal surfaces of a given pair of occluding teeth at the same time. Consequently, simultaneous examination of multiple biting movements is not possible, necessitating prolonged examination time.
Modern dentistry requires improved techniques for accurate evaluation of the contact points between occlusal surfaces. A method which avoids the aforenoted shortcomings of such prior art methods and makes possible the more accurate evaluation of the mode of contact between a pair of occluding teeth has been disclosed in applicant's Japanese Pat. No. 865,363, which issued June 23, 1977. In that method, a thin coating material is applied to the occlusal surface of one tooth of a pair of occluding teeth by means of a small brush. When both members of the pair of occluding teeth are brought into occluding relationship with each other, the coating material transfers at the points of contact from the coated occlusal surface to the uncoated occlusal surface. If the bite surface is too high, a bite plane correction can be made by scraping or filing the marked contact points to the extent necessary to achieve the proper bite contact.
An improved method of utilizing a plurality of transferable coatings of contrasting colors for marking contact points at predetermined areas on the occlusal surface of at least one pair of occluding teeth is the subject of applicant's copending U.S. patent application filed concurrently herewith and entitled Method of Marking Contact Points on the Occluding Surface of a Dental Restorative, Ser. No. 870,654, filed Jan. 19, 1978. In the method of the copending U.S. application, a coating of each color is applied to predetermined areas of the occlusal surface of a tooth or tooth impression molding. The coated occlusal surface is then brought into occluding relationship with a natural tooth or a dental restorative whereupon a portion of the previously applied coating in each predetermined area is transferred to the corresponding predetermined area of the occlusal surface of the natural tooth or restorative, but only at each contact point located within the corresponding predetermined area.
The coating composition of applicant's Japanese patent contains 10-30 percent of weight of a fluid paraffin, 30-40 percent by weight of vaseline, 10-20 percent by weight of glycerin and organic coloring. Such composition has certain properties which prevent the utilization of the methods of the aforesaid Japanese patent and of the aforesaid copending U.S. patent application to their maximum extent. First, although such composition can be applied as a thin coating of less than about half the thickness of the standard bite paper, thereby permitting visual examination of the contact points and a more accurate evaluation thereof than bite paper, this coating still has a finite thickness which prevents an even more accurate evaluation which an even thinner coating would facilitate. In addition, such coating composition is relatively insoluble and/or nondispersible in water, thereby precluding removal from the coated areas and contact points by a water rinse. It is extremely desirable to be able to remove the coating material by a water rinse, particularly when the coating is on a tooth in the mouth. In addition, the components of such composition are not readily compatible, and vigorous mixing conditions are required to fabricate the composition. The composition of the present invention is an improvement over, and otherwise has all of the advantageous properties of, the coating composition of the aforesaid Japanese patent.